This superb tuner App from TC Electronics is an emulation of their PolyTune tuner pedal - the world's first polyphonic tuner. Like its physical counterpart, this great little App lets guitarists to see the state of tune of all six strings at once! You simply strum all strings and see instantly which, if any, need tuning... then when you play a single note the display changes automatically to a conventional needle-style LED display. ...Read more »